Sensor Module Failure Diagnosis Using Redundant Gyro and Acceleration Signals

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Solution Overview

Problem

Existing systems struggle to accurately determine which inertial force sensor fails when redundancy is implemented, as they can only identify a failure but not specify which sensor is malfunctioning.

Innovation Solution

A method and sensor module utilizing a first and second sensor element to detect angular velocity around a common axis and a third sensor element to detect acceleration in a perpendicular direction, with a failure diagnosis circuit comparing signals to diagnose normality and perform further diagnostics when necessary.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If redundancy is implemented by using multiple inertial force sensors, then reliability against failure is improved, but the ability to determine which specific sensor fails deteriorates

Engineering Contradiction:
Improvereliability against failureVSAvoidinformation about which sensor fails
Core Design Contradiction:
ReliabilityVSLoss of information

Solution Approach 1:

The patent introduces a third sensor element (acceleration sensor) as an intermediary to mediate the failure diagnosis between the two angular velocity sensors. By comparing the acceleration signal with the angular velocity signals, the system can identify which angular velocity sensor has failed, thus resolving the information loss problem while maintaining reliability through redundancy

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces the mechanical comparison method (directly comparing two angular velocity sensors) with a physics-based substitution method. It uses the physical relationship between angular velocity and angular acceleration to substitute one sensor type (acceleration sensor) for another (angular velocity sensor) in the diagnosis process, enabling precise failure identification

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If only two angular velocity sensors are used for comparison, then device complexity is reduced, but measurement precision for failure diagnosis deteriorates

Engineering Contradiction:
Improvesensor configuration complexityVSAvoidfailure diagnosis precision
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The patent changes the diagnostic parameter from direct angular velocity comparison to a multi-parameter approach involving both angular velocity and angular acceleration. By utilizing the derivative relationship between these parameters, the system achieves higher measurement precision in failure diagnosis without significantly increasing device complexity

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The third sensor element serves multiple functions: it acts as a backup sensor, provides diagnostic information, and enables precise failure identification. This multi-functionality approach improves measurement precision while keeping the overall device complexity manageable by reusing the additional sensor for multiple purposes

Inventive Principle:
Principle #6Universality (Multi-functionality)

Data Source

PatentEP4431872B1Method for diagnosing failure in sensor module and sensor module
Publication Date: 2026.04.08 SEIKO EPSON CORP
  • EP4431872B1 patent drawingFigure 1~2
  • EP4431872B1 patent drawingFigure 3
  • EP4431872B1 patent drawingFigure 4

AI summary

A method for diagnosing a failure in a sensor module includes: a first diagnosis step of diagnosing that when a comparison result between a first angular velocity based on an output signal of a first sensor element detecting an angular velocity around a first axis and a second angular velocity based on an output signal of a second sensor element detecting an angular velocity around the first axis satisfies a first standard, the first sensor element and the second sensor element are normal; and a second diagnosis step of performing failure diagnosis of the first sensor element using the first angular velocity signal or the second angular velocity signal and an acceleration signal based on an output signal of a third sensor element detecting an acceleration in a second-axis direction when the comparison result does not satisfy the first standard.